Blood pressure in acute stroke

See Articles pages 364 and 374 Although great advances have been made in stroke medicine in the past two decades, some questions about treatment in the acute phase of stroke remain. One such question is how to manage blood pressure? Blood pressure is often increased in acute ischaemic and haemorrhagic stroke, and fi ndings from epidemiological studies suggest that high blood pressure in the acute phase is associated with poor outcome. The results of three large randomised clinical trials on blood pressure lowering in acute stroke—the Chinese Antihypertensive Trial in Acute Ischaemic Stroke, the Intensive Blood Pressure Reduction in Acute Cerebral Haemorrhage Trial (INTERACT-2), and the Scandinavian Candesartan Acute Stroke Trial—suggest that treatment should diff er according to the type of stroke. In The Lancet Neurology, fi ndings from two Articles provide new evidence for the importance of blood pressure in acute stroke. In one study, using data from the population-based Oxford Vascular Study, Urs Fischer and colleagues compared prestroke blood pressure values with blood pressure measured in the acute phase, and assessed whether this diff ers in ischaemic versus haemorrhagic stroke. Patients with intracerebral haemorrhage had a steeper rise in blood pressure, higher blood pressure in the acute phase, and a more substantial fall within the fi rst 24 h than did patients with ischaemic stroke. In the other study, Lisa Manning and colleagues did a post-hoc analysis of the INTERACT-2 trial—a randomised trial of intensive versus guideline blood pressure lowering in acute intracerebral haemorrhage—assessing the prognostic signifi cance of blood pressure variability in the hyperacute phase (fi rst 24 h) and the acute phase (days 2–7) after intracerebral haemorrhage. Episodic hypertension, single high systolic blood pressure, and variability of blood pressure in the hyperacute and the acute phases of an intracerebral haemorrhage were predictors of poor functional outcome. The fi ndings from these two studies suggest that patients with ischaemic stroke caused by smallvessel disease, and patients with deep or posterior haemorrhages, have higher blood pressure after stroke than patients with other ischemic stroke aetiologies or lobar haemorrhages, and when compared with recent pre-morbid measurements also have a steeper increase in blood pressure. These are important fi ndings, indicating that the eff ects of blood pressure should be diff erentiated and managed, according to not only the type of stroke, but also to aetiology or lesion location. Such diff erentiation should be a key area for future research. For clinicians, the data presented in the papers suggest that we should closely monitor blood pressure in acute stroke. In patients with intracerebral haemorrhage, we should strive to maintain blood pressure at a constant level. However, the investigators showed an association between increasing blood pressure variability and greater intensity of blood pressure-lowering treat ment. An intriguing question therefore remains: if high variability in blood pressure worsens outcome, and greater intensity of treatment increases variability, should blood pressure really be lowered? If so, how much should it be lowered and what is the best method to achieve the target level? In ischaemic stroke, blood pressure variability has been previously associated with poor outcome, and an association between high blood pressure and poor outcome has been shown in several populations. However, there is no compelling evidence that lowering blood pressure is benefi cial. Therefore, the prognostic signifi cance of blood pressure variability in acute ischaemic stroke is an important topic for further investigation. The Articles in The Lancet Neurology add to the evidence suggesting that blood pressure management in haemorrhagic stroke is important, hence treatment should diff er according to type of stroke, and sudden changes and variability in blood pressure should be avoided. Findings from two large stroke trials with an expected blood pressure-lowering eff ect are anticipated in 2014. Both trials have included patients with either ischaemic or haemorrhagic stroke and will add important evidence regarding blood pressure management in the acute phase.